QML Windows element behaviour has changed from Qt 5.9 to Qt 5.12.

User reported us that following code used to work on Qt 5.9 but does not work since 5.12.

Qt support has tested it on Qt 5.9, 5.12 and 5.14.

import QtQuick 2.6
import QtQuick.Window 2.2

Rectangle
{
	width: 300
	height: 200

        Window
	{
		id: ventanaPrueba

		visible: true

		width: 300
		height: 200

		modality: Qt.ApplicationModal

		Text
		{
			id: texto

			text: qsTr("Prueba")
		}
	}
}

Code does work on Qt 5.12 and 5.14 if Window line is changed to

property var ventana: Window

If QQuickView is used there is no issue on Qt 5.12 and 5.14

Example project has been attached.

By changing the rotatingsquare.qml's line 9 the behavior can be noticed.